[PATCH v1 1/3] x86/cpufeatures: Add {required,disabled} feature configs

From: Xin Li (Intel)
Date: Thu Feb 01 2024 - 00:47:34 EST

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From: "H. Peter Anvin (Intel)" <hpa@xxxxxxxxx>

To prepare for auto-generating a header with required and disabled
feature masks based on build config, add feature Kconfig items:
- X86_REQUIRED_FEATURE_x
- X86_DISABLED_FEATURE_x
which are set to "y" if their preconditions are met.

X86_CMPXCHG64 and X86_CMOV are required features, thus renamed to
X86_REQUIRED_FEATURE_CX8 and X86_REQUIRED_FEATURE_CMOV.

Signed-off-by: H. Peter Anvin (Intel) <hpa@xxxxxxxxx>
Signed-off-by: Xin Li (Intel) <xin@xxxxxxxxx>
---
arch/x86/Kconfig | 4 +-
arch/x86/Kconfig.cpu | 16 +-
arch/x86/Kconfig.cpufeatures | 149 ++++++++++++++++++
arch/x86/include/asm/asm-prototypes.h | 2 +-
arch/x86/include/asm/atomic64_32.h | 2 +-
arch/x86/include/asm/bitops.h | 4 +-
arch/x86/include/asm/cmpxchg_32.h | 4 +-
arch/x86/include/asm/required-features.h | 4 +-
arch/x86/lib/Makefile | 2 +-
arch/x86/lib/cmpxchg8b_emu.S | 2 +-
lib/atomic64_test.c | 2 +-
.../arch/x86/include/asm/required-features.h | 4 +-
12 files changed, 178 insertions(+), 17 deletions(-)
create mode 100644 arch/x86/Kconfig.cpufeatures

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index e78071049121..8bf28685d582 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -120,7 +120,7 @@ config X86
select ARCH_SUPPORTS_LTO_CLANG
select ARCH_SUPPORTS_LTO_CLANG_THIN
select ARCH_USE_BUILTIN_BSWAP
- select ARCH_USE_CMPXCHG_LOCKREF if X86_CMPXCHG64
+ select ARCH_USE_CMPXCHG_LOCKREF if X86_REQUIRED_FEATURE_CX8
select ARCH_USE_MEMTEST
select ARCH_USE_QUEUED_RWLOCKS
select ARCH_USE_QUEUED_SPINLOCKS
@@ -3066,4 +3066,6 @@ config HAVE_ATOMIC_IOMAP

source "arch/x86/kvm/Kconfig"

+source "arch/x86/Kconfig.cpufeatures"
+
source "arch/x86/Kconfig.assembler"
diff --git a/arch/x86/Kconfig.cpu b/arch/x86/Kconfig.cpu
index b9224cf2ee4d..68f97eabece6 100644
--- a/arch/x86/Kconfig.cpu
+++ b/arch/x86/Kconfig.cpu
@@ -358,6 +358,10 @@ config X86_P6_NOP
depends on X86_64
depends on (MCORE2 || MPENTIUM4 || MPSC)

+config X86_REQUIRED_FEATURE_NOPL
+ def_bool y
+ depends on X86_64 || X86_P6_NOP
+
config X86_TSC
def_bool y
depends on (MWINCHIP3D || MCRUSOE || MEFFICEON || MCYRIXIII || MK7 || MK6 || MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M686 || M586MMX || M586TSC || MK8 || MVIAC3_2 || MVIAC7 || MGEODEGX1 || MGEODE_LX || MCORE2 || MATOM) || X86_64
@@ -366,21 +370,27 @@ config X86_HAVE_PAE
def_bool y
depends on MCRUSOE || MEFFICEON || MCYRIXIII || MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M686 || MK8 || MVIAC7 || MCORE2 || MATOM || X86_64

-config X86_CMPXCHG64
+config X86_REQUIRED_FEATURE_CX8
def_bool y
depends on X86_HAVE_PAE || M586TSC || M586MMX || MK6 || MK7

# this should be set for all -march=.. options where the compiler
# generates cmov.
-config X86_CMOV
+config X86_REQUIRED_FEATURE_CMOV
def_bool y
depends on (MK8 || MK7 || MCORE2 || MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M686 || MVIAC3_2 || MVIAC7 || MCRUSOE || MEFFICEON || X86_64 || MATOM || MGEODE_LX)

+# this should be set for all -march= options where the compiler
+# generates movbe.
+config X86_REQUIRED_FEATURE_MOVBE
+ def_bool y
+ depends on MATOM
+
config X86_MINIMUM_CPU_FAMILY
int
default "64" if X86_64
default "6" if X86_32 && (MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M686 || MVIAC3_2 || MVIAC7 || MEFFICEON || MATOM || MCRUSOE || MCORE2 || MK7 || MK8)
- default "5" if X86_32 && X86_CMPXCHG64
+ default "5" if X86_32 && X86_REQUIRED_FEATURE_CX8
default "4"

config X86_DEBUGCTLMSR
diff --git a/arch/x86/Kconfig.cpufeatures b/arch/x86/Kconfig.cpufeatures
new file mode 100644
index 000000000000..7ae978c904e6
--- /dev/null
+++ b/arch/x86/Kconfig.cpufeatures
@@ -0,0 +1,149 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# x86 feature bits (see arch/x86/include/asm/cpufeatures.h) that are
+# either REQUIRED to be enabled, or DISABLED (always ignored) for this
+# particular compile-time configuration. The tests for these features
+# are turned into compile-time constants via the generated
+# <asm/featuremasks.h>.
+#
+# The naming of these variables *must* match asm/cpufeatures.h.
+#
+
+config X86_REQUIRED_FEATURE_ALWAYS
+ def_bool y
+
+config X86_REQUIRED_FEATURE_CPUID
+ def_bool y
+ depends on X86_64
+
+config X86_REQUIRED_FEATURE_UP
+ def_bool y
+ depends on !SMP
+
+config X86_REQUIRED_FEATURE_FPU
+ def_bool y
+ depends on !MATH_EMULATION
+
+config X86_REQUIRED_FEATURE_PAE
+ def_bool y
+ depends on X86_64 || X86_PAE
+
+config X86_REQUIRED_FEATURE_PSE
+ def_bool y
+ depends on X86_64 && !PARAVIRT_XXL
+
+config X86_REQUIRED_FEATURE_PGE
+ def_bool y
+ depends on X86_64 && !PARAVIRT_XXL
+
+config X86_REQUIRED_FEATURE_MSR
+ def_bool y
+ depends on X86_64
+
+config X86_REQUIRED_FEATURE_FXSR
+ def_bool y
+ depends on X86_64
+
+config X86_REQUIRED_FEATURE_XMM
+ def_bool y
+ depends on X86_64
+
+config X86_REQUIRED_FEATURE_XMM2
+ def_bool y
+ depends on X86_64
+
+config X86_REQUIRED_FEATURE_LM
+ def_bool y
+ depends on X86_64
+
+config X86_DISABLED_FEATURE_UMIP
+ def_bool y
+ depends on !X86_UMIP
+
+config X86_DISABLED_FEATURE_VME
+ def_bool y
+ depends on X86_64
+
+config X86_DISABLED_FEATURE_K6_MTRR
+ def_bool y
+ depends on X86_64
+
+config X86_DISABLED_FEATURE_CYRIX_ARR
+ def_bool y
+ depends on X86_64
+
+config X86_DISABLED_FEATURE_CENTAUR_MCR
+ def_bool y
+ depends on X86_64
+
+config X86_DISABLED_FEATURE_PCID
+ def_bool y
+ depends on !X86_64
+
+config X86_DISABLED_FEATURE_PKU
+ def_bool y
+ depends on !X86_INTEL_MEMORY_PROTECTION_KEYS
+
+config X86_DISABLED_FEATURE_OSPKE
+ def_bool y
+ depends on !X86_INTEL_MEMORY_PROTECTION_KEYS
+
+config X86_DISABLED_FEATURE_LA57
+ def_bool y
+ depends on !X86_5LEVEL
+
+config X86_DISABLED_FEATURE_PTI
+ def_bool y
+ depends on !MITIGATION_PAGE_TABLE_ISOLATION
+
+config X86_DISABLED_FEATURE_RETPOLINE
+ def_bool y
+ depends on !MITIGATION_RETPOLINE
+
+config X86_DISABLED_FEATURE_RETPOLINE_LFENCE
+ def_bool y
+ depends on !MITIGATION_RETPOLINE
+
+config X86_DISABLED_FEATURE_RETHUNK
+ def_bool y
+ depends on !MITIGATION_RETHUNK
+
+config X86_DISABLED_FEATURE_UNRET
+ def_bool y
+ depends on !MITIGATION_UNRET_ENTRY
+
+config X86_DISABLED_FEATURE_CALL_DEPTH
+ def_bool y
+ depends on !MITIGATION_CALL_DEPTH_TRACKING
+
+config X86_DISABLED_FEATURE_LAM
+ def_bool y
+ depends on !ADDRESS_MASKING
+
+config X86_DISABLED_FEATURE_ENQCMD
+ def_bool y
+ depends on !INTEL_IOMMU_SVM
+
+config X86_DISABLED_FEATURE_SGX
+ def_bool y
+ depends on !X86_SGX
+
+config X86_DISABLED_FEATURE_XENPV
+ def_bool y
+ depends on !XEN_PV
+
+config X86_DISABLED_FEATURE_TDX_GUEST
+ def_bool y
+ depends on !INTEL_TDX_GUEST
+
+config X86_DISABLED_FEATURE_USER_SHSTK
+ def_bool y
+ depends on !X86_USER_SHADOW_STACK
+
+config X86_DISABLED_FEATURE_IBT
+ def_bool y
+ depends on !X86_KERNEL_IBT
+
+config X86_DISABLED_FEATURE_FRED
+ def_bool y
+ depends on !X86_FRED
diff --git a/arch/x86/include/asm/asm-prototypes.h b/arch/x86/include/asm/asm-prototypes.h
index 076bf8dee702..fb1fe8547b3a 100644
--- a/arch/x86/include/asm/asm-prototypes.h
+++ b/arch/x86/include/asm/asm-prototypes.h
@@ -15,7 +15,7 @@
#include <asm/fred.h>
#include <asm/gsseg.h>

-#ifndef CONFIG_X86_CMPXCHG64
+#ifndef CONFIG_X86_REQUIRED_FEATURE_CX8
extern void cmpxchg8b_emu(void);
#endif

diff --git a/arch/x86/include/asm/atomic64_32.h b/arch/x86/include/asm/atomic64_32.h
index 3486d91b8595..d58488dbbafe 100644
--- a/arch/x86/include/asm/atomic64_32.h
+++ b/arch/x86/include/asm/atomic64_32.h
@@ -22,7 +22,7 @@ typedef struct {
ATOMIC64_EXPORT(atomic64_##sym)
#endif

-#ifdef CONFIG_X86_CMPXCHG64
+#ifdef CONFIG_X86_REQUIRED_FEATURE_CX8
#define __alternative_atomic64(f, g, out, in...) \
asm volatile("call %P[func]" \
: out : [func] "i" (atomic64_##g##_cx8), ## in)
diff --git a/arch/x86/include/asm/bitops.h b/arch/x86/include/asm/bitops.h
index 990eb686ca67..e3e69dca8edb 100644
--- a/arch/x86/include/asm/bitops.h
+++ b/arch/x86/include/asm/bitops.h
@@ -321,7 +321,7 @@ static __always_inline int variable_ffs(int x)
asm("bsfl %1,%0"
: "=r" (r)
: "rm" (x), "0" (-1));
-#elif defined(CONFIG_X86_CMOV)
+#elif defined(CONFIG_X86_REQUIRED_FEATURE_CMOV)
asm("bsfl %1,%0\n\t"
"cmovzl %2,%0"
: "=&r" (r) : "rm" (x), "r" (-1));
@@ -378,7 +378,7 @@ static __always_inline int fls(unsigned int x)
asm("bsrl %1,%0"
: "=r" (r)
: "rm" (x), "0" (-1));
-#elif defined(CONFIG_X86_CMOV)
+#elif defined(CONFIG_X86_REQUIRED_FEATURE_CMOV)
asm("bsrl %1,%0\n\t"
"cmovzl %2,%0"
: "=&r" (r) : "rm" (x), "rm" (-1));
diff --git a/arch/x86/include/asm/cmpxchg_32.h b/arch/x86/include/asm/cmpxchg_32.h
index b5731c51f0f4..61449e666e0e 100644
--- a/arch/x86/include/asm/cmpxchg_32.h
+++ b/arch/x86/include/asm/cmpxchg_32.h
@@ -7,7 +7,7 @@
* you need to test for the feature in boot_cpu_data.
*/

-#ifdef CONFIG_X86_CMPXCHG64
+#ifdef CONFIG_X86_REQUIRED_FEATURE_CX8
#define arch_cmpxchg64(ptr, o, n) \
((__typeof__(*(ptr)))__cmpxchg64((ptr), (unsigned long long)(o), \
(unsigned long long)(n)))
@@ -63,7 +63,7 @@ static inline bool __try_cmpxchg64(volatile u64 *ptr, u64 *pold, u64 new)
return success;
}

-#ifndef CONFIG_X86_CMPXCHG64
+#ifndef CONFIG_X86_REQUIRED_FEATURE_CX8
/*
* Building a kernel capable running on 80386 and 80486. It may be necessary
* to simulate the cmpxchg8b on the 80386 and 80486 CPU.
diff --git a/arch/x86/include/asm/required-features.h b/arch/x86/include/asm/required-features.h
index 7ba1726b71c7..13018e507f76 100644
--- a/arch/x86/include/asm/required-features.h
+++ b/arch/x86/include/asm/required-features.h
@@ -23,13 +23,13 @@
# define NEED_PAE 0
#endif

-#ifdef CONFIG_X86_CMPXCHG64
+#ifdef CONFIG_X86_REQUIRED_FEATURE_CX8
# define NEED_CX8 (1<<(X86_FEATURE_CX8 & 31))
#else
# define NEED_CX8 0
#endif

-#if defined(CONFIG_X86_CMOV) || defined(CONFIG_X86_64)
+#if defined(CONFIG_X86_REQUIRED_FEATURE_CMOV) || defined(CONFIG_X86_64)
# define NEED_CMOV (1<<(X86_FEATURE_CMOV & 31))
#else
# define NEED_CMOV 0
diff --git a/arch/x86/lib/Makefile b/arch/x86/lib/Makefile
index 72cc9c90e9f3..493259ed0cc9 100644
--- a/arch/x86/lib/Makefile
+++ b/arch/x86/lib/Makefile
@@ -62,7 +62,7 @@ ifeq ($(CONFIG_X86_32),y)
lib-y += string_32.o
lib-y += memmove_32.o
lib-y += cmpxchg8b_emu.o
-ifneq ($(CONFIG_X86_CMPXCHG64),y)
+ifneq ($(CONFIG_X86_REQUIRED_FEATURE_CX8),y)
lib-y += atomic64_386_32.o
endif
else
diff --git a/arch/x86/lib/cmpxchg8b_emu.S b/arch/x86/lib/cmpxchg8b_emu.S
index 1c96be769adc..4bc06bd1aee1 100644
--- a/arch/x86/lib/cmpxchg8b_emu.S
+++ b/arch/x86/lib/cmpxchg8b_emu.S
@@ -7,7 +7,7 @@

.text

-#ifndef CONFIG_X86_CMPXCHG64
+#ifndef CONFIG_X86_REQUIRED_FEATURE_CX8

/*
* Emulate 'cmpxchg8b (%esi)' on UP
diff --git a/lib/atomic64_test.c b/lib/atomic64_test.c
index d9d170238165..e68bde45b962 100644
--- a/lib/atomic64_test.c
+++ b/lib/atomic64_test.c
@@ -254,7 +254,7 @@ static __init int test_atomics_init(void)
pr_info("passed for %s platform %s CX8 and %s SSE\n",
#ifdef CONFIG_X86_64
"x86-64",
-#elif defined(CONFIG_X86_CMPXCHG64)
+#elif defined(CONFIG_X86_REQUIRED_FEATURE_CX8)
"i586+",
#else
"i386+",
diff --git a/tools/arch/x86/include/asm/required-features.h b/tools/arch/x86/include/asm/required-features.h
index 7ba1726b71c7..13018e507f76 100644
--- a/tools/arch/x86/include/asm/required-features.h
+++ b/tools/arch/x86/include/asm/required-features.h
@@ -23,13 +23,13 @@
# define NEED_PAE 0
#endif

-#ifdef CONFIG_X86_CMPXCHG64
+#ifdef CONFIG_X86_REQUIRED_FEATURE_CX8
# define NEED_CX8 (1<<(X86_FEATURE_CX8 & 31))
#else
# define NEED_CX8 0
#endif

-#if defined(CONFIG_X86_CMOV) || defined(CONFIG_X86_64)
+#if defined(CONFIG_X86_REQUIRED_FEATURE_CMOV) || defined(CONFIG_X86_64)
# define NEED_CMOV (1<<(X86_FEATURE_CMOV & 31))
#else
# define NEED_CMOV 0
--
2.43.0

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